The plan is divided into 2 parts, both concerned with CBD and humans. PART I: our previous results suggest that CBD interferes with delta 9 THC effects. Further experiments showed that CBD potentiates the depressant and blocks the excitability and "hyperemotional" responses of delta 9 THC. The double interference of CBD on delta 9THC effects suggests that marihuanas with high content of CBD would induce more depression and less "high" or hallucination on humans than should be expected by their delta 9 THC content. To test this volunteers will receive, in a double blind procedure, either 5-20 mg of delta 9THC alone or delta 9THC plus CBD (mixtures of 1:1 to 1:4 of each). The drugs will be delivered as smoke through a spirometer and cardiac rate, a time producing task and psychological effects will be measured as described by us. PART II: reports on anti-epileptic property of marihuana are known since 1840. Delta 9 THC and Synhexyl protect animals from convulsions. We demonstated that CBD decreased the susceptibility of rat dorsal hippocampus to seizure discharges and protect mice against cardiazol convulsions. Therefore CBD may have anti-epileptic property. In a pilot study we administered 10 mg daily of CBD to 4 volunteers during 21 days; urine and blood analysis, ECG and EEG, physical and psychiatric examinations revealed that CBD was without toxicity. We plan now to give CBD to epileptic patients, in a 3 step experiment: 1) healthy volunteers will receive 50-200 mg CBD during 30 days for further toxicological studies; 2) epileptic patients will receive CBD in a double blind procedure and with complete control as in step 1; 3) ambulatory epileptic patients will be randomly assigned to one of 3 groups (2 doses of CBD or Tridione); follow up and EEG will be performed every 15 days as usually done in the Dept. of Neurology at EPM.